Dear Kim,
In message <20090216200502.1e25c494.kim.phill...@freescale.com> you wrote:
>
> Trent Piepho <xy...@speakeasy.org> wrote:
...
> > But what systems are affected by the problem? For instance ms7750se only
> > has ".rodata", not even ".rodata.str1.4". So should it get changed too?
> >
> > There are CPUs that have a special segment for byte aligned data. Does
> > u-boot support any of these CPUs? I don't know. But changing ".rodata" to
> > ".rodata*" could break a system if ".rodata1" was supposed to be picked up
> > by a ".*data*1" somewhere else in the linker script. It seems like people
> > who know the platform would be less likely to get caught by this.
> >
> > Or take something like mpc8220, which has this for a text segment:
> > *(.text)
> > *(.fixup)
> > *(.got1)
> > . = ALIGN(16);
> > *(.rodata)
> > *(.rodata1)
> > *(.rodata.str1.4)
> > *(.eh_frame)
> >
> > Why is the start of rodata aligned to 16 bytes? I'd guess some sort of I/D
> > cache issue. Though aren't fixup and got1 data, not code? I can't
> > find any docs on what the differences between fixup, got, got1, and got2
> > are. It seems like current gcc only uses got2. The mpc8220 ld script also
> > lists fixup a second time, in the reloc section, a mistake that probably
> > doesn't break anything since I think gcc hasn't used fixup in some time.
> >
> > Anyway, not knowing if it's ok to delete fixup and got1, I would change
> > this to:
> > *(.text)
> > *(.fixup)
> > *(.got1)
> > . = ALIGN(16);
> > *(.eh_frame)
> > *(SORT_BY_ALIGNMENT(SORT_BY_NAME(.rodata*)))
> >
> > eh_frame should go before rodata* since it has has a larger alignment, but
> > now rodata isn't 16 byte aligned like it was before. Does that matter? I
> > doubt it, but I don't know for sure.
> >
>
> WD, do you have a response to the above? Otherwise, I'll put this
> in my queue:
Please don't. I really want to see this fixed for ALL affected boards,
not only for a small subset so everbody forgets it again and we run
into it later again and again.
Trent - you have obviously already spend a lot of effort into
analyzing this code - most probably more time than any other of us.
Based on your experience and the effort you already spent I think it
would be best if you could provided a patch to fix all boards.
Thanks in advance.
Best regards,
Wolfgang Denk
--
DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: w...@denx.de
"'Tis true, 'tis pity, and pity 'tis 'tis true."
- Poloniouius, in Willie the Shake's _Hamlet, Prince of Darkness_
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